Turnbull is well known to have his own world view and, at the very least, provides a stylistic contrast to Tony Abbott, who was widely, if not always accurately, portrayed as cravenly loyal to the US. So, it was inevitable that the premier would see his words and deeds in Washington scrutinised for evidence of greater 'independence'; that perennial itch within Australia’s foreign policy.

Turnbull’s visit was, by most accounts, successful on that score. The Prime Minister’s keynote address conveyed the impression of a supportive ally, especially in the fight against Islamic State, albeit led by someone whose loyalty is tempered by independent judgment and a willingness to offer as well as to receive advice, as demonstrated by Turnbull’s pitch for the US to ratify the UN Convention on the Law of the Sea.

If there were lingering American doubts raised by Canberra’s decision not to reinforce Australian forces committed to Iraq and Syria, despite a formal US request, they did not appear to tarnish Turnbull’s Beltway interactions. This may owe something to Turnbull’s less-noticed move, announced during a mid-January lightning visit to Kabul, to augment the ADF non-combat mission to Afghanistan by 20 personnel to 270.

The premier’s stop-off in Hawaii to visit the US Pacific Command (PACOM) en route home is also worth highlighting. PACOM’s outspoken chief, Admiral Harry Harris, has repeatedly called out Chinese misbehaviour in the South China Sea and elsewhere to the extent that he has sometimes appeared at odds with the Obama administration’s more cautious line. That the Prime Minister made time to visit PACOM, where Australia has a senior officer attached, sends a signal of institutional alliance solidarity and that he understands Australia’s future strategic challenges lie in Asia. However vexed Turnbull may be about the Thucydides trap in Sino-US relations, it also makes sense to have the ear of Sparta’s frontline commander, whoever the next commander-in-chief will be.

These calibrations suggest Turnbull can and will steer a smart course on alliance management. Such focused attention on Mr Turnbull, however, may encourage the easy perception that, with right leader in Canberra, the alliance will take care of itself. Little attention in last week’s commentary was given over to the mechanics of the alliance itself and the tests it faces ahead. It’s as if the co-driver and his presumed influence on route selection matter to the exclusion of the car.

That is because years of continuous coalition operations in the Middle East and Afghanistan, regular joint exercises, and deepening institutional integration have fostered the perception of an alliance in good health, unencumbered by serious barriers to defence and intelligence cooperation. A few tweaks under the bonnet and she’ll be right.

At first glance, not much appears awry under the hood. While the US-Japan alliance recently acquired an alliance management coordination mechanism, Australian units are used to operating, in combat, under US command. Australian warships have been embedded into the US Seventh Fleet, while the US Marine presence augurs for an expanded American military footprint on Australian soil. Time and again, we are told that while there are no grounds for complacency, the alliance’s engine still fires on all cylinders. (OK, I really shouldn’t belabour the automotive metaphor).

However, in the run-up to Turnbull’s visit there was an illuminating revelation of discord in a National Interest article by Andrew Shearer and Michael Green, who have enough experience at the policy coalface to give them credibility as canaries. Four years after President Obama announced the rotation of up to 2500 US Marines through northern Australia — as the lead element of the US re-balance — Washington and Canberra remain at odds over who pays for their supporting facilities and infrastructure.

If the two allies cannot agree on something as basic as this, involving relatively modest sums of money, one has to wonder about the prospects.

Canberra will, before long, have to decide how actively to participate in ballistic missile defence (beyond the enabling role it already plays in hosting the joint facility at Pine Gap) – an issue that is already causing ructions in Washington’s alliance with South Korea. Then there was the Australian Defence department’s undoubted oversight in not informing the US about the sale of Darwin port to a Chinese state entity, despite its proximity to the US Marine presence. That looked something rather like complacency.

Prime Minister Turnbull may also have to contend with more domestic politics on alliance matters than he bargained for. Opposition spokesman Stephen Conroy’s entry into the debate on freedom of navigation operations in the South China Sea, effectively calling the government’s bluff by advocating for an Australian operational response, suggests a new willingness to test out the limits of bipartisan consensus on national security.

These hiccups and potential hurdles pose individual challenges to the alliance which effective political leadership can certainly help to overcome. But we also need to step back and reflect that the existing templates for alliance management were developed when the strategic focus of attention was in the Middle East, not Australia’s own region. Planning for defence contingencies in which Australia is required to fight alongside US forces in the Pacific theatre, (where the US has not engaged in a single combat operation since the Vietnam War), is an entirely different proposition, unsuited to ad hoc responses, or niche unit contributions of the kind that Canberra and the ADF have grown used to.

A scenario in which the US and China are fighting each other, or possibly even a more limited US armed intervention on the Korean peninsula, would also be far harder for Canberra to say 'no' to, as well as requiring a much a deeper degree of alliance integration and a bigger scale of military effort on Australia’s part than anything experienced for decades. Conflict, of course, is far from inevitable. But preparing and planning for high-intensity warfare in the Indo-Pacific is bound to take up an increasing amount of alliance bandwidth in the years ahead.

Tom Switzer’s commentary 'Turnbull the clear-eyed realist' was among the more perceptive analyses of the prime minister’s trip to Washington. However, even Switzer concedes, that where China is concerned, the best that Australia can probably hope for in the Turnbull era is to be a 'helpful passenger'. That being the case, it’s time to start thinking more about the car and the road ahead.